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Schulze H, Sandhoff K. Sphingolipids and lysosomal pathologies. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:799-810. [PMID: 24184515 DOI: 10.1016/j.bbalip.2013.10.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 10/16/2013] [Accepted: 10/19/2013] [Indexed: 01/12/2023]
Abstract
Endocytosed (glyco)sphingolipids are degraded, together with other membrane lipids in a stepwise fashion by endolysosomal enzymes with the help of small lipid binding proteins, the sphingolipid activator proteins (SAPs), at the surface of intraluminal lysosomal vesicles. Inherited defects in a sphingolipid-degrading enzyme or SAP cause the accumulation of the corresponding lipid substrates, including cytotoxic lysosphingolipids, such as galactosylsphingosine and glucosylsphingosine, and lead to a sphingolipidosis. Analysis of patients with prosaposin deficiency revealed the accumulation of intra-endolysosmal vesicles and membrane structures (IM). Feeding of prosaposin reverses the storage, suggesting inner membrane structures as platforms of sphingolipid degradation. Water soluble enzymes can hardly attack sphingolipids embedded in the membrane of inner endolysosomal vesicles. The degradation of sphingolipids with few sugar residues therefore requires the help of the SAPs, and is strongly stimulated by anionic membrane lipids. IMs are rich in anionic bis(monoacylglycero)phosphate (BMP). This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.
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Affiliation(s)
- Heike Schulze
- LIMES, Membrane Biology & Lipid Biochemistry Unit, c/o Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, D-53115 Bonn, Germany
| | - Konrad Sandhoff
- LIMES, Membrane Biology & Lipid Biochemistry Unit, c/o Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, D-53115 Bonn, Germany.
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Abstract
Gangliosides are the main glycolipids of neuronal plasma membranes. Their surface patterns are generated by coordinated processes, involving biosynthetic pathways of the secretory compartments, catabolic steps of the endolysosomal system, and intracellular trafficking. Inherited defects in ganglioside biosynthesis causing fatal neurodegenerative diseases have been described so far almost exclusively in mouse models, whereas inherited defects in ganglioside catabolism causing various clinical forms of GM1- and GM2-gangliosidoses have long been known. For digestion, gangliosides are endocytosed and reach intra-endosomal vesicles. At the level of late endosomes, they are depleted of membrane-stabilizing lipids like cholesterol and enriched with bis(monoacylglycero)phosphate (BMP). Lysosomal catabolism is catalyzed at acidic pH values by cationic sphingolipid activator proteins (SAPs), presenting lipids to their respective hydrolases, electrostatically attracted to the negatively charged surface of the luminal BMP-rich vesicles. Various inherited defects of ganglioside hydrolases, e.g., of β-galactosidase and β-hexosaminidases, and of GM2-activator protein, cause infantile (with tetraparesis, dementia, blindness) and different protracted clinical forms of GM1- and GM2-gangliosidoses. Mutations yielding proteins with small residual catabolic activities in the lysosome give rise to juvenile and adult clinical forms with a wide range of clinical symptomatology. Apart from patients' differences in their genetic background, clinical heterogeneity may be caused by rather diverse substrate specificities and functions of lysosomal hydrolases, multifunctional properties of SAPs, and the strong regulation of ganglioside catabolism by membrane lipids. Currently, there is no treatment available for neuronal ganglioside storage diseases. Therapeutic approaches in mouse models and patients with juvenile forms of gangliosidoses are discussed.
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Conzelmann E, Sandhoff K. Glycolipid and glycoprotein degradation. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 60:89-216. [PMID: 3310533 DOI: 10.1002/9780470123065.ch3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- E Conzelmann
- Institut für Organische Chemie und Biochemie, Universität Bonn, Federal Republic of Germany
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Kresse H, Glössl J. Glycosaminoglycan degradation. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 60:217-311. [PMID: 3310531 DOI: 10.1002/9780470123065.ch4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- H Kresse
- Institute of Physiological Chemistry, University of Münster, Federal Republic of Germany
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Sandhoff K. The GM2-gangliosidoses and the elucidation of the beta-hexosaminidase system. ADVANCES IN GENETICS 2002; 44:67-91. [PMID: 11597000 DOI: 10.1016/s0065-2660(01)44072-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- K Sandhoff
- Institut für Organische Chemie und Biochemie der Universität Bonn, Germany
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Kalanj-Bognar S, Rundek T, Furac I, Demarin V, Cosović C. Leukocyte lysosomal enzymes in Alzheimer's disease and Down's syndrome. J Gerontol A Biol Sci Med Sci 2002; 57:B16-21. [PMID: 11773202 DOI: 10.1093/gerona/57.1.b16] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Previous studies suggested the possibility of accelerated lysosomal degradation of brain gangliosides in Alzheimer's disease (AD). As AD pathology affects both neural and nonneural tissues, the aim of this study was to determine possible changes of glycosphingolipid metabolism in available peripheral cells in AD and Down's syndrome (DS). The activities of several lysosomal enzymes involved in catabolism of gangliosides and sulfatides were measured in leukocytes from subjects with dementia of the Alzheimer type, DS, and age-matched controls, by fluorimetry and spectrophotometry using specific substrates. The results showed a statistically significant increase of beta-galactosidase activity in both dementia of the Alzheimer type and DS leukocytes when compared with age-matched controls (p <.01 and p <.05, respectively; Student's t test). Not significantly increased activities of beta-galactosidase, beta-hexosaminidase, beta-hexosaminidase A, and slightly decreased activity of arylsulfatase A were observed in control leukocytes with aging. Our results indicate that a metabolic dysfunction and the acceleration of at least some lysosomal catabolic pathways are present in AD and DS nonneural cells.
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Hou Y, McInnes B, Hinek A, Karpati G, Mahuran D. A Pro504 --> Ser substitution in the beta-subunit of beta-hexosaminidase A inhibits alpha-subunit hydrolysis of GM2 ganglioside, resulting in chronic Sandhoff disease. J Biol Chem 1998; 273:21386-92. [PMID: 9694901 DOI: 10.1074/jbc.273.33.21386] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The GM2 gangliosidoses are caused by mutations in the genes encoding the alpha- (Tay-Sachs) or beta- (Sandhoff) subunits of heterodimeric beta-hexosaminidase A (Hex A), or the GM2 activator protein (AB variant), a substrate-specific co-factor for Hex A. Although the active site associated with the hydrolysis of GM2 ganglioside, as well as part of the binding site for the ganglioside-activator complex, is associated with the alpha-subunit, elements of the beta-subunit are also involved. Missense mutations in these genes normally result in the mutant protein being retained in the endoplasmic reticulum and degraded. The mutations associated with the B1-variant of Tay-Sachs are rare exceptions that directly affect residues in the alpha-active site. We have previously reported two sisters with chronic Sandhoff disease who were heterozygous for the common HEXB deletion allele. Cells from these patients had higher than expected levels of mature beta-protein and residual Hex A activity, approximately 20%. We now identify these patients' second mutant allele as a C1510T transition encoding a beta-Pro504 --> Ser substitution. Biochemical characterization of Hex A from both patient cells and cotransfected CHO cells demonstrated that this substitution (a) decreases the level of heterodimer transport out of the endoplasmic reticulum by approximately 45%, (b) lowers its heat stability, (c) does not affect its Km for neutral or charged artificial substrates, and (d) lowers the ratio of units of ganglioside/units of artificial substrate hydrolyzed by a factor of 3. We concluded that the beta-Pro504 --> Ser mutation directly affects the ability of Hex A to hydrolyze its natural substrate but not its artificial substrates. The effect of the mutation on ganglioside hydrolysis, combined with its effect on intracellular transport, produces chronic Sandhoff disease.
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Affiliation(s)
- Y Hou
- The Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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Novak A, Callahan JW, Lowden JA. Classification of disorders of GM2 ganglioside hydrolysis using 3H-GM2 as substrate. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1199:215-23. [PMID: 8123671 DOI: 10.1016/0304-4165(94)90118-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Rates of GM2 ganglioside hydrolysis by fibroblasts from normal controls and patients with GM2 gangliosidosis were measured in situ, with cells growing in tissue culture by assaying the decrease in cell-incorporated 3H-GM2 over time, and in vitro by assaying the rate of 3H-GM2 hydrolysis using fibroblast extracts in the presence of no additives, sodium taurocholate, and GM2 activator protein. In tissue culture, normal cells hydrolyzed cell-incorporated GM2 while fibroblasts from patients with GM2 gangliosidosis did not. The half life of GM2 in normal fibroblasts was 78 hours. In vitro, only normal fibroblast extracts hydrolyzed GM2 in the absence of additives. In the presence of 10 mM sodium taurocholate, rates of GM2 hydrolysis by normal fibroblast extracts were increased 5-16-fold, fibroblast extracts from AB and B1 variant patients hydrolyzed GM2 at normal rates, cell extracts from patients with Tay-Sachs disease hydrolyzed GM2 at nearly normal rates, and cell extracts from Sandhoff disease patients hydrolyzed GM2 at about 10% of normal rates. In the presence of 1 microgram of GM2 activator, rates of GM2 hydrolysis by normal fibroblast extracts were increased 8-25-fold, fibroblast extracts from a patient with the AB variant hydrolyzed GM2 at normal rates, and cell extracts from other variants of GM2 gangliosidosis did not hydrolyze GM2. The results suggest that measuring the persistence of 3H-GM2 in tissue culture over time will detect any variant of GM2 gangliosidosis and may be the ideal way to test for the presence of this disease. Variants can be distinguished by assaying the hydrolysis of 3H-GM2 using cell extracts in the absence of additives, with sodium taurocholate, and with activator.
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Affiliation(s)
- A Novak
- Division of Neurosciences, Hospital for Sick Children, Toronto, Canada
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Wakamatsu N, Kobayashi H, Miyatake T, Tsuji S. A novel exon mutation in the human beta-hexosaminidase beta subunit gene affects 3' splice site selection. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)45894-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Nardocci N, Bertagnolio B, Rumi V, Angelini L. Progressive dystonia symptomatic of juvenile GM2 gangliosidosis. Mov Disord 1992; 7:64-7. [PMID: 1532632 DOI: 10.1002/mds.870070113] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
A 9-year-old boy showed a progressive generalized dystonia, with onset at the age of 4 years, combined with mental deterioration and behavioral disturbances. The values of beta-hexosaminidase activities studied in plasma, leukocytes, and fibroblasts obtained using two different substrates (MUG-NAc and MUG-NAc-6-S) were significantly reduced but higher than in Tay-Sachs disease and similar to those found in the juvenile chronic form of GM2 gangliosidosis. With anticholinergic therapy, for 1.5 years, the dystonic symptoms did not progress and the boy can still care for himself and attend school. The description of another case of the disease, clinically expressed as dystonia, corroborates the existence of a dystonic phenotype of GM2 gangliosidosis.
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Affiliation(s)
- N Nardocci
- Department of Child Neurology, Istituto Nazionale Neurologico, Besta, Milan, Italy
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Den Tandt WR, Scharpe S. Characteristics of hexosaminidase A in homogenates of white blood cells using methylumbelliferyl-N-acetyl-beta-D-glucosaminide-6-sulphate as substrate. Clin Chim Acta 1991; 199:231-6. [PMID: 1837501 DOI: 10.1016/0009-8981(91)90116-t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Using methylumbelliferyl-N-acetyl-beta-D-glucosaminide-6-sulphate as a substrate hexosaminidase A activity was measured in leukocyte homogenates with a one-step method without the need of thermoinactivation. According to the buffer system used--acetate or citrate--the enzyme has pH optima of 3.5 and 4, respectively, and is linear during at least 1 h of incubation. The enzyme is resistant to mechanical inactivation by homogenization or to freezing and thawing and is thermostable between 0 and 37 degrees C but it is rapidly inactivated at 50 degrees C. This thermoinactivation is retarded by acidification of the homogenate. The latency of the enzyme is in agreement with its known lysosomal localization. Like most lysosomal enzymes, hexosaminidase A binds to Concanavalin A. After homogenization of leukocytes and repeated freezing and thawing, about 60% of the enzyme is present in the supernatant. Hexosaminidase A activity was stimulated by taurocholate between 0.05 and 0.1 M and inhibited by dimethylsulfoxide, dimethylformamide, N-acetylglucosamine and N-acetylgalactosamine. No pronounced difference was noted in specific activity of a homogenate of mononuclear cells, granulocytes or total leukocytes.
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Affiliation(s)
- W R Den Tandt
- University of Antwerp (UIA), Faculty of Medicine, Antwerp-Wilrijk, Belgium
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Fusch C, Huenges R, Moser HW, Sewell AC, Roggendorf W, Kustermann-Kuhn B, Poulos A, Carey WF, Harzer K. A case of combined Farber and Sandhoff disease. Eur J Pediatr 1989; 148:558-62. [PMID: 2744019 DOI: 10.1007/bf00441558] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We describe a patient with the biochemically established combination of Farber and Sandhoff disease. A 6-month-old girl of consanguineous Turkish parents presented with hoarseness, stridor, scattered skin nodules, painful swelling of hand joints and ankles, and cherry-red macular spots. Until the age of 2 years her motor and physical condition deteriorated distinctly, however her mental state remained unchanged. A biopsied skin nodule disclosed lysosomal inclusions within storage cells that were typical of Farber disease (curved tubular structures). However, other inclusions (e.g. zebra bodies) were also found. Biochemical findings included ceramide accumulation in skin nodules and cultured fibroblasts, impaired ceramide degradation on loading of cultured fibroblasts with radioactive sphingomyelin, profoundly decreased ceramidase activity in fibroblasts as well as total beta-hexosaminidase activity in fibroblasts and serum, absent hexosaminidase A and B bands on cellogel zymograms, increased urinary oligosaccharide excretion of the Sandhoff disease type, and a partial reduction of ceramidase and total beta-hexosaminidase activities in fibroblasts from her father. A diagnosis of combined Farber and Sandhoff disease was made. The effect of both enzyme deficiencies on the clinical manifestations in this patient and the genetic basis of this combination require further studies.
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Affiliation(s)
- C Fusch
- Universitäts-Kinderklinik, Rümelinstrasse Tübingen, Federal Republic of Germany
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Novotny JR, Brendler S, Kytzia HJ, Sandhoff K, Gaedicke G. Hexosaminidase I indicates maturation disarrangement in acute leukemias. HAEMATOLOGY AND BLOOD TRANSFUSION 1987; 31:191-4. [PMID: 2965081 DOI: 10.1007/978-3-642-72624-8_42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- J R Novotny
- Abteilung Pädiatrie II, Universitäts-Kinderklinik, Ulm/Donau, FRG
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Warner TG, De Kremer RD, Applegarth D, Mock AK. Diagnosis and characterization of GM 2 gangliosidosis type II (Sandhoff disease) by analysis of the accumulating N-acetyl-glucosaminyl oligosaccharides with high performance liquid chromatography. Clin Chim Acta 1986; 154:151-64. [PMID: 3955841 DOI: 10.1016/0009-8981(86)90026-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The N-acetyl-glucosaminyl oligosaccharides excreted in urine and accumulating in tissues of Sandhoff disease patients have been analyzed and characterized using a combination of high performance liquid chromatography and 500 MHz proton magnetic resonance spectroscopy. Delineation between infantile and juvenile onset forms of the disease was possible, as the latter forms had 6- to 13-fold lower levels of urinary oligosaccharides. Patients from a geographically isolated population deme in the La Rioja region of Argentina had urinary oligosaccharides similar to unrelated non-Argentinean patients with identical clinical phenotype. Together, these results indicate that the urinary oligosaccharides serve as useful indicators of the mutation differences or clinical heterogeneity within this disease only in cases of markedly differing clinical presentation. Analysis of the accumulating metabolites in liver, kidney, pancreas, lung and spleen, showed a similar oligosaccharide pattern which differed dramatically from brain. These results suggest the possibility of tissue specific regulation of oligosaccharide biosynthesis since there are notable differences between neural and visceral tissues.
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Sonderfeld S, Brendler S, Sandhoff K, Galjaard H, Hoogeveen AT. Genetic complementation in somatic cell hybrids of four variants of infantile GM2 gangliosidosis. Hum Genet 1985; 71:196-200. [PMID: 2933318 DOI: 10.1007/bf00284572] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cell hybridizations between fibroblasts of four variants (B, O, AB, and B1) of infantile GM2 gangliosidosis were performed. Cocultivated as well as hybrid cells were analyzed for their capability to degrade exogenously added [3H]-GM2. Hybridization of variant AB fibroblasts with fibroblasts of variant O, variant B, or variant B1 resulted in an enhanced rate of GM2 hydrolysis, showing intergenic complementation. Similar restoration of GM2 catabolism was observed after hybridization of variant B1 cells with variant O, but not with variant B cells. These results indicate that B1 cells carry a mutation in the gene locus for the alpha-subunit of beta-hexosaminidase. Studies of the processing of immature enzyme in variant B1 cells showed the presence of alpha-precursors and mature alpha-chains, but at a lower level as compared to normal cells.
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Kytzia HJ, Sandhoff K. Evidence for two different active sites on human beta-hexosaminidase A. Interaction of GM2 activator protein with beta-hexosaminidase A. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)39645-x] [Citation(s) in RCA: 169] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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